KR100452898B1 - Pattern forming method and method for disposing a chemical liquid - Google Patents

Abstract

The dimensional difference in the whole board | substrate and the micro area | region of the pattern formed in the resist film is suppressed, and the defect which arises at the image development process is reduced.

A pre-treatment before supplying a developer for applying an oxidizing liquid having an oxidizing action to the surfaces of the photosensitive resist films 301a and 301b formed in the resist film and oxidizing the surface of the resist film with the oxidizing liquid to form the oxide layer 310 is performed. A step of supplying a developing solution 302 to the photosensitive resist film whose surface is oxidized to develop the resist film, and supplying a cleaning solution to the surface of the substrate to be treated to clean the substrate. do.

Description

PATTERN FORMING METHOD AND METHOD FOR DISPOSING A CHEMICAL LIQUID}

TECHNICAL FIELD This invention relates to the pattern formation method in manufacture of a semiconductor device, ULSI, an electronic circuit component, a liquid crystal display element.

With the miniaturization of semiconductor elements and the large diameter of substrates, the occurrence of fatal defects due to the development by the conventional developing method, the nonuniformity of pattern dimensions in the substrate surface and in the chip, etc. have become a big problem. To solve these problems, solutions are generally explored to further complicate the process, such as controlling the developing time, improving the developer, weakening the rinse liquid, extending the rinse time, and increasing the rinse recovery. There is a need for large new processes.

In the development process of the substrate after the conventional exposure and heat treatment, generally, the developer is directly discharged to the target substrate to start development, or the pure water is discharged to sprinkle at low rotation to form a thin water layer on the surface of the substrate, so that the substrate is wetted in advance. By improving the wettability with respect to the developing solution on the surface of a to-be-processed substrate by appearance, the developing solution is discharged on a board | substrate and the image development is used.

In development pretreatment using pure water, it was possible to prevent the developer from splashing on the substrate to some extent by wetting the substrate in advance, thereby improving in-plane uniformity. However, with the miniaturization of the processing dimension, there arises a problem of dimensional difference in the micro area, which cannot be solved by the conventional method, and there is a need to develop more precisely. In addition, a large number of defects due to the development cause occur, and there is a serious problem of causing a decrease in yield. These problems cannot be solved in the conventional developing step, and pretreatment with pure water shows no effect on these problems.

As described above, as the size of the semiconductor element becomes smaller and the size of the substrate becomes larger, the size difference of the micro area in the developing step and the size difference across the entire surface of the substrate occur, and development needs to be performed more precisely. In addition, it was necessary to reduce the fatal defects caused by the phenomenon.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pattern formation method capable of suppressing the dimensional difference in the entire substrate and the minute region of the pattern formed in the resist film and reducing defects in the developing step.

1 is a diagram showing a schematic configuration of a chemical liquid applying apparatus according to a first embodiment.

FIG. 2 is a view for explaining a resist film forming method using the chemical liquid applying device shown in FIG.

3 is a view for explaining a resist film forming method using the chemical liquid applying apparatus shown in FIG.

4 is a view for explaining a resist film forming method using the chemical liquid applying apparatus shown in FIG.

Fig. 5 is a view for explaining a resist and a developer formed by a conventional resist film forming method.

Fig. 6 is a view for explaining a resist film and a developer which have been treated by the resist film forming method according to the first embodiment.

FIG. 7 is a diagram showing ozone water treatment time with respect to dimensional deviation of a resist pattern within a substrate surface to be treated;

8 shows a state in which organic molecules are attached to a surface of a resist.

9 is a view for explaining the action and effect in washing by ozone water pretreatment.

10 is a diagram showing a result of reducing the number of defects after development according to the first embodiment;

Fig. 11 is a diagram showing a change in contact angle of a developer with respect to ozone water treatment time.

Fig. 12 is a diagram showing a contact angle with respect to the elapsed time from the dropping of a developing solution of an ozone water untreated substrate.

Fig. 13 is a diagram showing the contact angle with respect to the elapsed time from the dropwise addition of the developing solution of the ozone water 30 second processing substrate.

Fig. 14 is a view for explaining a resist film forming method according to the second embodiment.

Fig. 15 is a view for explaining a resist film forming method according to the second embodiment.

Fig. 16 is a view for explaining a resist film forming method according to the second embodiment.

Fig. 17 is a view for explaining the operation and effects in the resist film forming method according to the third embodiment.

Fig. 18 is a diagram explaining the waste liquid treatment of ozone water according to the fourth embodiment.

Fig. 19 is a diagram explaining the waste liquid treatment of ozone water according to the fourth embodiment.

20 is a view for explaining the waste liquid treatment of ozone water according to the fourth embodiment.

Fig. 21 is a diagram showing a time change of the ozone gas concentration of ozone water mixed in the developing solution.

Fig. 22 is a diagram showing the relationship with the pH of the time required for the residual ozone concentration to be 1/10.

<Explanation of symbols for the main parts of the drawings>

100: substrate to be processed

101: fixture

102: rotating mechanism

103: chemical liquid supply nozzle

104: rectification plate

110: substrate to be processed

[Configuration]

This invention is comprised as follows in order to achieve the said objective.

(1) The pattern formation method of this invention applies the process of apply | coating a photosensitive resist film on a to-be-processed substrate, the process of exposing to the said photosensitive resist film, and apply | coating the oxidizing liquid which has an oxidation effect on the surface of the exposed photosensitive resist film. Performing a pretreatment before supplying a developer for oxidizing the surface of the resist film with the oxidizing liquid to form an oxide layer, supplying a developer to the photosensitive resist film whose surface is oxidized, and developing the resist film; And supplying a cleaning liquid to the surface of the substrate to be treated, thereby cleaning the substrate.

By applying an oxidizing liquid having an oxidizing action to the photosensitive resist film after exposure and oxidizing the surface of the photosensitive resist film, the interaction between ionic molecules, particle molecules, and the resist surface present in the developing solution in the developing step can be changed. have. From a macro perspective, it means changing the contact angle between the exposed portion on the substrate and the surface of the resist film on the non-exposed portion, and as a result, the initial stage of development caused by the magnitude of the area ratio of the exposed portion to the non-exposed portion in the local area. The difference in the developing speed can be reduced, and the speed and direction of the developer flow in the initial stage of development can be made uniform. The dissolved product produced during the development flows along with the developer through the flow of the developer, but by controlling the flow of the developer, it is possible to control the product generated during the development.

The surface of the organic particles generated by the development by lowering the contact angle of the resist surface by modifying the resist surface before development by using a low concentration ozone water that does not erode the resist as a liquid having an oxidation action on the resist surface on the substrate to be treated. There is a remarkable effect in improving the yield by reducing the effect of the interaction generated through the developer or the cleaning solution between the molecule and the resist surface molecule and preventing adhesion of organic particles during development and cleaning.

By this, the uniformity of the processing pattern in a developing process can be improved remarkably, and generation | occurrence | production of the fatal defect in a developing process can be remarkably reduced. Therefore, the yield in a developing process can be improved significantly.

Preferred embodiments of the present invention are recorded below.

The pretreatment is performed until the contact angle between the developer and the cleaning solution with respect to the photosensitive resist film decreases.

In the pretreatment, the oxide layer is not formed more than 5 nm in the depth direction of the resist film. As the oxidizing liquid, an aqueous solution having an ozone concentration of 5 ppm or less is used. An erosion layer in which the polymer constituting the photosensitive resist film in the oxide layer is decomposed by the oxidizing liquid is not formed.

In the pretreatment, a step of forming an eroded layer in which the polymer constituting the resist film in the oxide layer is decomposed by the oxidizing liquid is less than 5 nm in the depth direction of the resist film, when the developer is supplied onto the photosensitive resist film. And a step of forming a swelling layer in which the developer is immersed in the erosion layer, and supplying the cleaning solution onto the substrate to be treated, and peeling the swelling layer.

By developing a thin swelling layer by infiltrating a developing solution with a resist surface layer at the time of image development, and peeling the said swelling layer at the time of washing | cleaning, there is a remarkable effect on the yield improvement by preventing organic particle from adhering to the resist surface.

When the developer is supplied to the photosensitive resist film, the developer and the developer discharge nozzle are relatively moved to form the developer film while supplying the developer to the surface of the photosensitive resist film by the developer discharge nozzle.

Uniformization of the development time in the scan phenomenon in which the developer and the developer discharge nozzle are relatively moved to supply the developer while supplying the developer to the developer discharge nozzle to the surface of the photosensitive resist film, and the liquid flow in the initial stage of development This has a remarkable effect on the uniformity of the resist processing dimension in the substrate surface due to the suppression of and the reduction of the development speed difference caused by the magnitude of the area ratio of the exposed portion and the non-exposed portion in the local area.

The step of applying the oxidizing liquid, thinning the liquid film made of the applied oxidizing liquid, and forming the developer film in a state where the thin film is formed.

By leaving a small liquid film on the substrate to be treated and supplying an alkaline liquid on the liquid film, alkali ions in the developer can be deactivated, thereby alleviating the difference in the development time between the development discharge start end and the development discharge end, Development start time can be matched in-plane, and development can be performed uniformly.

Moreover, with respect to the process using ozone water, the means for rapidly decomposing and discharging ozone remaining in the used ozone water is configured as follows.

(2) The chemical liquid treatment method of the chemical liquid used in the substrate treatment of the present invention comprises the steps of supplying an alkaline solution to a chemical liquid holding portion provided outside the substrate to be treated with a thin film formed on its main surface, and ozone on the principal surface of the substrate to be treated. Supplying ozone water, which is an aqueous solution containing water, to modify the surface of the thin film, and inducing ozone water used for the modification to the chemical liquid holding portion in which the alkaline solution is held, and ozone in ozone water induced in the chemical liquid holding portion. And a step of decomposing by the alkaline solution held in the chemical liquid holding part, and discharging the alkaline solution and ozone water from which ozone is decomposed from the chemical liquid holding part.

For example, ozone water used for surface modification of the thin film on the main surface of the substrate to be treated can be treated before development.

(3) The pattern formation method of this invention is a process of supplying alkaline solution to the chemical | medical agent holding part provided in the outer side of the to-be-processed substrate in which the thin film was formed in the main surface, and ozone water which is an aqueous solution containing ozone on the main surface of the said to-be-processed substrate Supplying the surface of the thin film to guide the ozone water used for the reforming to the chemical liquid holding portion in which the alkaline solution is held, and the ozone in the ozone water induced in the chemical liquid holding portion to the chemical liquid holding portion. Decomposing by the retained alkali solution, supplying the alkali solution on the main surface of the substrate to be modified, and selectively etching the thin film with the alkali solution, thereby removing the alkaline solution used for etching. And a step of discharging the alkaline solution and ozone water from which ozone is decomposed from the chemical solution holding unit. And it characterized in that.

The ozone water used for surface modification of the thin film on the to-be-processed substrate main surface can be processed before image development.

(4) The pattern formation method of this invention supplies the alkali solution on the main surface of the to-be-processed board | substrate with which the thin film was formed in the main surface, and selectively etchs the said thin film with the said alkaline solution, and the alkaline solution used for the said etching. Is used for cleaning while supplying ozone water, which is an aqueous solution containing ozone, to the main surface of the to-be-processed substrate which has been etched and cleaning the main surface of the substrate. A step of introducing ozone water into the chemical liquid holding portion, a step of decomposing ozone in ozone water induced in the chemical liquid holding portion with an alkaline solution held in the chemical liquid holding portion, and the treated substrate to be cleaned. And drying the alkaline solution and ozone water from which ozone is decomposed from the chemical liquid holding unit. The.

For example, the ozone water used for the rinsing step after development can be treated.

(5) The pattern formation method of this invention supplies the alkali solution to the chemical | medical agent holding part provided in the outer side of the to-be-processed substrate in which the thin film was formed in the main surface, and ozone water which is an aqueous solution containing ozone on the main surface of the said to-be-processed substrate Supplying and modifying the surface of the thin film, inducing ozone water used for the reforming to the chemical liquid holding portion in which the alkaline solution is held, and supplying an alkaline solution on a main surface of the substrate to be treated in which the thin film is modified. And selectively etching the thin film to retain the alkaline solution used for etching in the chemical liquid holding portion, and to remove the ozone water used for cleaning while exposing the main surface of the substrate to be treated with the thin film to be washed with ozone water. A process of introducing the ozone in the ozone water induced in the chemical liquid holding portion to the chemical liquid holding portion; Process for drying step, the cleaned substrate to be processed to break by re-solution and, and the alkali solution and the ozone water decomposition of ozone, characterized in that it comprises a step of emission in the drug solution holding portion.

The surface modification of the thin film on the substrate to-be-processed surface before image development and the ozone water used for the rinsing process after image development can be performed.

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]

(1) Embodiment 1

First, the chemical | medical solution coating apparatus used by this embodiment is demonstrated. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the chemical | medical solution coating apparatus which concerns on 1st Embodiment of this invention.

As shown in Fig. 1, a holding table 101 on which a substrate 100 to be processed is fixed to a surface thereof is connected to a rotating mechanism 102 for rotating the holding table 101. As shown in Figs. On the fixing base 101, a chemical liquid supply nozzle 103 for discharging chemical liquids, such as ozone water, a developing solution, and a cleaning liquid, is provided on the surface of the substrate 100 to be processed. The chemical liquid supply nozzle 103 is driven by a drive mechanism to move relative to the substrate to be processed. In accordance with the relative movement of the chemical liquid supply nozzle 103, the chemical liquid is applied onto the substrate to be processed by discharging the chemical liquid onto the substrate to be processed.

The chemical liquid supply nozzle 103 has a plurality of supply ports, and the ozone water, the developer, and the cleaning liquid (pure water) are respectively supplied to independent nozzles. In addition, the chemical liquid supply nozzle 103 supplies the chemical liquid by scanning the substrate to be processed in one direction on the outside of the substrate circumference when discharging the chemical liquid.

Moreover, above the to-be-processed board | substrate 100, it is a stirring mechanism which stirs the chemical | medical solution apply | coated on the to-be-processed board | substrate 100, Comprising: The rectifying plate 104 which consists of a flat rotary disk with an intake hole in the center, And a lifting mechanism of the rectifying plate is provided.

In addition, the chemical liquid supply nozzle 103 is not limited to the above form as long as it can supply the chemical liquid uniformly on the substrate to be processed. In addition, the stirring mechanism is not limited to the above-mentioned form as long as there exists an action which stirs a developing solution during image development.

Next, the pattern formation method using this developer application apparatus is demonstrated with reference to FIGS.

As shown in Fig. 2A, an antireflection film and a chemically amplified resist are applied onto the substrate 100 to be processed, and a desired pattern is reduced and projected by a KrF excimer laser through a exposure mask. The substrate to be processed is subjected to heat treatment (PEB) and conveyed to the developing unit, and then held by the fixing table 101.

Then, as shown in Fig. 2B, a low concentration ozone water of about 2 ppm is discharged onto the surface of the substrate 100 to be treated by the chemical liquid supply nozzle 103 to form an ozone water liquid film 201, Only the resist surface is slightly oxidized by exposing the entire surface of the substrate 100 to ozone water for 5 to 30 seconds.

Subsequently, as shown in FIG. 2C, the ozone water liquid film 201 formed on the substrate 100 is rotated by rotating the substrate 100 at 2000 rpm by the rotating mechanism 102. ).

Then, as shown in Fig. 3D, the chemical liquid supply nozzle is scanned from one end of the substrate 100 to the other end while discharging the developer in the form of a curtain with the chemical liquid supply nozzle 103. Thus, the developer film 202 is formed on the surface of the substrate 100 to be processed, and the development of the resist film on the substrate to be processed is performed for 30 to 45 seconds. Although it was necessary for 60 second to perform conventional development, developing time could be performed for 30 to 45 second by performing ozone water pretreatment.

As shown in Fig. 3E, after the time for which a desired pattern is obtained in the resist film has elapsed by development, ultrapure water is discharged onto the substrate to be processed by a cleaning nozzle, the development is stopped, and the developer And lysis products and the like. Then, after cleaning with pure water for 10 seconds, as shown in Fig. 3 (f), the surface 100 of the substrate 100 is rotated at high speed by the rotating mechanism 102 and the pure water 203 'of the surface is removed. Roots. Then, as shown in Fig. 4G, the surface of the substrate 100 to be processed is dried to finish the developing step.

The surface of the resist on the substrate to be treated is oxidized by low concentration ozone water treatment. As a result, most of the carboxylic acid is formed on the surface of the resist, the wettability increases with respect to pure water and the developing solution, and is modified to a more hydrophilic resist surface. There exists an effect and the effect shown below regarding image development and washing | cleaning.

First, the action and effect in the phenomenon by ozone water pretreatment are demonstrated.

The effect of ozone water pretreatment on the developer is prominent in the very early stages of development, in the process of the developer contacting the resist surface. Usually, as shown in Fig. 5, when the developer 302 is directly contained in the exposed resists 301a (exposed part) and 30lb (non-exposed part), the alkali ions 303, which are molecules of the developer, Due to the intermolecular interactions between the molecules on the resist surface, a particularly strong repulsive force is received at the non-exposed portion 30lb. Therefore, the developer 302 is splashed on the surface of the non-exposed portion of the resist 30lb, and the exposed portion 301a having a wide non-exposed portion on the periphery causes a difference in development start time when viewed from the entire surface of the untreated substrate. Deviation occurs in the development time at each point.

This development unevenness generated on the substrate affects the flow direction and the flow direction of the developer after the start of development. This flow carries the dissolved product in the resist generated by the development during development, and the dissolved product is only carried within the substrate. By these factors, the nonuniformity arises in the board | substrate surface in the dimension of the pattern after image development.

As shown in Fig. 6A, an oxidation layer 310 is formed on the surfaces of the resists 301a and 301b by subjecting the resist surface to oxidation before development with ozone water. As shown in Fig. 6B, since the contact angle of the developer 302 to the oxide layer 310 is lower than that of the resist, the intermolecular interaction between the surface molecules of the resist 301 and the alkali ions 303 in the developer is It is weakened, and the developer is not splashed on the surface of the resist immediately after the developer is discharged, thereby preventing development unevenness and variations in developing time.

In addition, due to the significant difference in the dissolution rate of the exposed portion 301a and the non-exposed portion 30lb with respect to the developer and the difference in contact angle on the surface, an effective resistance friction occurs to the flow of the developer on the substrate, and the flow velocity of the developer flows. , A deviation occurs in the direction, and a deviation of the development occurs on the substrate. By oxidizing both the exposed portion and the non-exposed portion by ozone water treatment, the difference in contact angle between the exposed portion and the non-exposed portion can be reduced, and the effective resistance friction can be reduced. For this reason, the flow of a developing solution is rectified and the dimensional uniformity of the pattern in a board | substrate surface improves.

Also, in the pattern region where the extremely fine exposed portion and the non-exposed portion are densely mixed, with respect to the exposed portion pattern, which should be developed rapidly, the intermolecular repulsion with respect to alkali ions in the developer by the adjacent non-exposed portion pattern is expected. And due to the attraction force from the exposed portion, on the dense pattern region, the force flowing in the horizontal direction so as to slide the region rather than the force moving in the lower exposed portion pattern acts on the alkali ions. As a result, in the early stage of development, the developer is splashed in the dense area of the pattern, and may hinder the penetration of alkali ions. Thus, the development of the pattern after development in comparison with the pattern area where the exposed part and the non-exposed part are not densely mixed. There is a difference in the dimensions.

By using low concentration ozone water as a pretreatment for development, the resist surface of the substrate to be treated is oxidized irrespective of the exposed portion and the non-exposed portion, thereby lowering the contact portion with the developer, thereby intermolecular interaction from the non-exposed portion with respect to alkali ions in the developer. The repulsive force is weakened. For this reason, the developing solution can be rapidly developed on the exposed portion without being splashed on the finely patterned region of the exposed portion and the non-exposed portion. As a result, generation | occurrence | production of the dimension difference of the dense | mixed area | region and the area | region which is not dense in the exposure part and the non-exposure part in the fine pattern which became a problem conventionally can be prevented.

In addition, in the initial stage of development, the time from when the developer film is formed to when the developer penetrates the resist surface and the actual development is started is reduced since the penetration into the resist surface can be accelerated by ozone water treatment. For this reason, the throughput in the developing step is improved.

The change in the ozone water treatment time of the dimensional deviation in the surface of the substrate of the resist pattern (0.15 µL / S, 0.118 µL / S) on the substrate to be processed by the method described in this embodiment is 7 is shown. By performing the ozone water treatment, a decrease in the 3σ value was clearly seen.

In addition, Table 1 shows the results of the in-plane uniformity improvement when the ozone water treatment is performed for 15 seconds.

O.15 μL / S dimension 15 seconds O ₃ treatment O.18 ㎛ L / S Dimension 0 _{3 for} 15 seconds 3σ / REF 68.40% 66.90%

In Table 1, 3σ / REF represents the ratio of 3σ of the dimensional deviation of the resist formed by ozone water treatment and 3σ of the dimensional deviation of the resist formed by the conventional method in percentage.

As shown in Table 1, it can be seen that the dimensional deviation in the substrate surface was reduced to 70% or less by the ozone water treatment as compared with the conventional method.

In addition, when the oxidizing action of ozone water is strong, not only is it oxidized on the surface of the resist film to form an oxide layer, but also the polymer constituting the resist film is decomposed in this oxide layer, and the oxide layer becomes an eroding layer. When the erosion layer (oxidized layer) is formed at 5 nm or more, the development is promoted more than necessary at the time of development, and the etching resistance as a mask in the etching step after the development step may deteriorate. Therefore, it is preferable to use ozone water having an ozone concentration of 5 ppm or less so that an erosion layer (oxidized layer) is not formed at 5 nm or more. More preferably, no erosion layer is formed.

On the other hand, by weakening the oxidizing action of ozone water, only the resist surface molecules can be oxidized without causing decomposition of the resist resin by ozone water, and it does not affect the etching resistance as a mask in the etching step after the developing step.

Next, the operation and effect in washing by ozone water pretreatment will be described.

As shown in Fig. 8, in the development process, the organic molecules 403 contained in the resist start to melt in the developing solution 402, which are precipitated by aggregation or rapid pH change in the developing solution or the cleaning solution. It is known that defects which reattach to the surface of the resist 401 occur. 8, reference numeral 400 denotes a substrate.

Conventionally, in order to remove these organic material reattachment defects, it has dealt with using a chemical liquid, lengthening a washing time, increasing washing frequency, etc. However, the current defect removal method focuses on how to remove a defect that has already been attached, and presupposes that a defect occurs in advance. The mechanism by which organic substance reattachment defects generate | occur | produce is considered as follows.

It is known that particles with organic molecules contained in a resist, which is a main component of a defect, generally have a large contact angle. The large contact angle means that the energy at the interface between organic particles and liquid molecules is large in pure water or in a developing solution. This means that the surface molecules of the organic particles are present in the liquid and next to each other in the cleaning solution (water) or the molecules of the developing solution are not energetically stable, so that the organic particles try to move to a more energy stable place. When the contact angle of the resist surface is large, the energy becomes large and unstable at the interface between the resist surface and water or the developing solution.When the organic particles present in the liquid come near the surface of the resist having a large contact angle, the surface molecules of the organic particles Rather than arranging water molecules and developer molecules adjacent to each other, the surface adjacent to the resist surface is more energy-efficient and stable.Resist surface molecules also arrange organic particle molecules than arranging water molecules or developer molecules adjacent to each other. One side is more energy stable. And organic particles are attached to the resist surface.

By performing the development pretreatment with the low concentration ozone water of the present invention, the resist surface is oxidized before development, and the effect of reducing the contact angle with respect to pure water and the developer is confirmed. Hydrophilicity increases on the surface of the resist whose contact angle is reduced by ozone water treatment. When water molecules and developer molecules are disposed adjacent to the surface of the resist, the energy at the interface decreases and becomes more stable energy. For this reason, as shown in FIG. 9, when the organic particle 403 approaches the oxide layer 410 of the resist 401 type | mold in the developing solution 402, it adjoins with a moisture molecule or a developing solution molecule, and an organic particle molecule. In the case of adjoining, the trade off of which is energy gain is performed, and when the adjoining water molecules or developer molecules are energetically stable, organic particles do not adhere to the resist surface. For this reason, the defect by organic substance repositioning is remarkably reduced.

In the ozone water treatment according to the present invention, this trade-off is used to reduce organic adhesion defects by making the surface of the resist surface molecules adjacent to the organic particle molecules more stable than the molecules of the organic particles. Since this technique does not generate adhesion defects as compared with the prior art, it is possible to realize a significant shortening of the cleaning time. Moreover, compared with the prior art, it is excellent in environmental point in that a chemical liquid is not used. However, since ozone water slightly remaining in water diffuses into the atmosphere, it is preferable to decompose ozone in ozone water when used in large quantities. When dissolving and discharging ozone water, it is preferable to perform the same means as in the fourth embodiment.

The reduction result of the number of defects after image development by this embodiment description method is shown in FIG. It can be seen that the present embodiment can completely eliminate the organic matter adhesion defect which becomes a fatal defect.

The contact angle with respect to the developing solution of the resist film was measured about the board | substrate which developed by the method of this embodiment description. The results are shown in Figs. 11, 12 and 13. 11 is a change in contact angle of the developer with respect to ozone water treatment time. The measurement was made about the exposed portion and the non-exposed portion. On the ozone water treatment time O seconds, that is, on the untreated substrate, the difference in contact angle between the exposed portion and the non-exposed portion can be seen about 10 degrees, but after 15 seconds, the difference was almost O.

12 and 13 are contact angles with respect to the elapsed time from the dropping of the developing solution of the ozone water untreated substrate and the ozone water treated substrate 30 seconds, respectively. As shown in Fig. 12, in the absence of ozone water treatment, a difference in contact angle of about 10 degrees was observed immediately after the dropping of the developing solution. The difference was decreased with time, but the difference was not zero. On the other hand, as shown in Fig. 13, there was no difference in contact angle between the exposed portion and the non-exposed portion on the substrate subjected to ozone water treatment for 30 seconds. From the above result, the remarkable effect was quantitatively supported by the developing process by ozone water treatment of this invention.

In the present embodiment, the concentration of ozone water is 2 ppm and the treatment is performed for 5 to 30 seconds. However, if the concentration has the effect of the present embodiment without damaging the resist, it depends on the value of the present embodiment. I never do that.

In addition, in this embodiment, although ozone water was used as a oxidizing liquid, it is not limited to ozone water as long as it is a liquid which has an oxidizing effect which does not erode the resist surface 5 nm or more similarly. For example, you may use the aqueous solution containing oxygen, carbon monoxide, etc., hydrogen peroxide solution, etc.

(2nd embodiment)

A resist film forming method of this embodiment will be described with reference to FIGS. 14 to 16.

First, an antireflection film and a chemically amplified resist are applied onto the substrate 100 to be treated, and a KrF excimer laser is used to reduce and project a desired pattern through an exposure reticle. The substrate is heat-treated and conveyed to a developing unit, and then held as a support (Fig. 14 (a)).

Similarly to the first embodiment, in the present invention, the ozone water liquid film 201 is formed by discharging low concentration ozone water of about 2 ppm onto the substrate to be discharged by the chemical liquid supply nozzle 103, and the whole surface of the substrate is covered with ozone water. The surface of the resist is slightly oxidized by hitting for 30 seconds (Fig. 14 (b)).

Subsequently, the ozone water liquid film 201 formed on the substrate is removed by sprinkling the ozone water 201 by rotating the substrate at 500 to 1000 rpm for 2 to 5 seconds, and the ozone water liquid film 201 on the order of several tens of microns is removed. Is left on the substrate (Fig. 14 (c)).

Next, while discharging the developing solution from the chemical liquid supply nozzle 103 in a curtain shape, the chemical liquid supply nozzle 103 is scanned from one end to the other end of the substrate 100 to a thickness of about 500 μm. The developer film 202 is formed (Fig. 15 (d)).

Subsequently, in order to remove alkali ions of the developer inactivated with ozone water and not to locally stagnate the resist dissolving product generated during development, the developer and ozone water are stirred on the substrate to be treated (Fig. 15 (e). )]. Agitation of the developer and ozone water 201 and 202 generates airflow on the surface of the substrate 100 by rotating the rectifying plate 104 having an intake hole in the center on the substrate to an appropriate height on the substrate 100. I was supposed to.

After the time for obtaining the desired pattern has elapsed, ultrapure water is discharged onto the substrate 100 to be processed by the chemical liquid supply nozzle 103 to stop the development, and the developer, the dissolved product, etc. are washed out (Fig. 15 ( f)].

After washing with pure water for 10 seconds, the substrate 100 to be processed is rotated at high speed and dried (Fig. 16 (g)). The development process is completed by the above (Fig. 16 (h)).

In addition, in this embodiment, although the rectifying plate which has the intake hole arrange | positioned on the board | substrate was used as a stirring mechanism, the form of a stirring mechanism does not matter if it has the same effect. For example, as another stirring mechanism, the mechanism which rotates the board | substrate itself, and agitates the developing solution on it, and the mechanism which stirs a developing solution by blowing inert gas on a board | substrate, etc. are considered to have the same effect.

Although the effect in image development and the effect in washing | cleaning are the same as that of 1st Embodiment, in addition, about 10 micrometers of ozone water liquid films are formed in a board | substrate in the initial stage of image development, the difference in image development start time on a board | substrate is alleviated. It works. In the case where the developer film is formed on the substrate by scanning the nozzle from one end to the other end of the substrate while discharging the developer in the form of a curtain with the chemical supply nozzle, the developing time at the scan start end and the scan end end on the substrate. The difference occurs, and the dimension of the pattern appears.

Therefore, by forming a low concentration ozone sap film capable of inactivating the alkali ions of the developer on the substrate, at the start of developer discharge, the alkali ions are inactivated by the ozone water on the substrate to slow down the development start time, and already in the vicinity of the developer discharge end. The ozone water on the substrate is deactivated by alkali, and the development time difference occurring at the scanning start end and the end of the developer discharge can be alleviated.

In addition, by performing ozone water treatment on the substrate to be treated and agitating during development, the amount of the chemical solution used is simply supplied by supplying a small amount of developer with a film thickness of about 500 μm through which the chemical liquid on the substrate can effectively flow. Can be reduced.

In the present embodiment, the concentration of ozone water is 2 ppm and the treatment is performed for 10 seconds. However, the concentration does not damage the resist and does not depend on the value of the present embodiment as long as the concentration has the effect of the present embodiment.

(Third embodiment)

Since the pattern formation method of this embodiment is the same as that of 1st embodiment, illustration is abbreviate | omitted.

An antireflection film and a chemically amplified resist are applied onto the substrate to be treated, and a KrF excimer laser is used to reduce and project a desired pattern through an exposure reticle. After heat-processing the said board | substrate and conveying to a developing unit, it maintains as a support body. In this embodiment, low concentration ozone water of about 3 ppm having a higher concentration than that of the first and second embodiments is discharged onto the discharge-treated substrate, and the entire surface of the substrate is oxidized with ozone water. Subsequently, by rotating the substrate at 2000 rpm, the liquid film of ozone water formed on the substrate is removed by sprinkling.

Then, the developer solution film is formed on the substrate by scanning the chemical solution supply nozzle from one end of the substrate to the other end in a straight line while discharging the developer solution in the form of a curtain with the chemical solution supply nozzle. After the time for obtaining the desired pattern has elapsed, ultrapure water is discharged from the cleaning nozzle onto the substrate to be processed, the development is stopped, and the developer, the dissolved product and the like are washed out. After washing with pure water for 10 seconds, the substrate is spun at high speed to dry.

The effect of ozone water treatment in development is the same as in the first embodiment. In this embodiment, in addition, it has the effect of recording below. That is, in this embodiment, since the ozone concentration of ozone water is higher than that of the first embodiment, by the ozone water treatment, the resist surface has more oxidized molecules than in the first embodiment, and the rate at which the polymer on the resist surface decomposes. Is elevated.

For this reason, as shown in Fig. 17, an alkaline developer penetrates into the surface layer of the resist surface during the development, and a slightly swelling layer 502 is formed on the surface of the resist 501. In the step of starting cleaning with pure water continuously from the development, the alkali concentration drops rapidly, so that the alkali in the swelling layer 502 formed on the resist tries to diffuse into the cleaning liquid 503 again. By the force acting at this time, the swelling layer 502 of the surface layer of the resist 501 can be peeled off, and any defects adhering on the resist 501 can be removed.

Conventionally, defects have been observed in which the poorly soluble layer on the surface of the resist is not sufficiently melted by development and adheres to the surface of the resist with a size of about several micrometers, but this defect was not found at all in this embodiment.

In the present embodiment, the concentration of ozone water is 3 ppm, and the treatment is performed for 5 to 30 seconds. However, if the concentration has the effect described in the present embodiment without damaging it further by only slightly swelling the resist surface, It does not depend on the value described in embodiment.

Hereinafter, embodiment which concerns on the chemical liquid processing method of the chemical liquid used for the process board | substrate is mentioned.

(4th embodiment)

In the developing step of the lithography process, when the developing solution is supplied to the main surface of the substrate to be processed, a flow of the developing solution occurs or a development delay occurs due to a difference in the surface state of the portion exposed and the portion not exposed in the previous step. There is a problem that the machining dimension precision is poor. Moreover, the defect resulting from the dissolution product which arises by etching a thin film of a developing solution arises, and there exists a problem that a yield falls.

As a method of solving these problems, the surface of a thin film is exposed to ozone water and the difference of surface state is eliminated. Moreover, the method of exposing the pattern after image development to ozone water, and oxidizing and removing the melt | dissolution product which adhered to the thin film has been performed. While ozone water has a very large effect on the developing process, problems such as corrosive downstream pipes and large environmental loads when flowed into rivers as drainage are a problem.

As a method of decomposing ozone, Patent Publication No. 2000-12535 describes a method of adding an alkaline chemical to an ozone waste liquid. However, in this technique, it was difficult to say that ozone is disposed of in the atmosphere from the ozone waste liquid before adding alkaline chemicals, so that ozone is completely decomposed.

In the following embodiment, the waste liquid treatment method of ozone water after ozone water treatment is demonstrated using FIGS. 18-20. In addition, the following ozone water treatment is not limited to the ozone water treatment demonstrated in 1st-3rd embodiment.

This embodiment is formed with an organic photosensitive resin film as a mask material for basic processing on a silicon substrate main surface in a semiconductor manufacturing process, and relates to a method for selectively processing an organic photosensitive resin film.

A chemically amplified resist having a sensitivity to ArF (wavelength 193 nm) is used for the photosensitive resin film, and the wiring processing pattern is transferred by the ArF exposure apparatus, and the heat treatment at 130 ° C. is performed after exposure.

As shown in Fig. 18A, the substrate to be processed 600 is placed on the substrate holding portion 601 of the developing apparatus. The substrate holding part 601 is provided with a rotation mechanism, and the substrate to be processed 600 can be rotated. A cup made of an inner cup 602 and an outer cup 603 is provided around the substrate 600. The cup is provided with an alkaline developer supply port 604 and a valve 606 for discharging the solution accumulated at the bottom of the cup.

Since the affinity between the exposed portions and the non-exposed portions of the chemically amplified resist film is large, the development of the chemically amplified resist film causes liquid migration due to the difference in affinity at the time of supplying the liquid. It was expected that dimensional variations would occur. Therefore, before supplying the developing solution, the first ozone water treatment step was performed in which the surface was slightly oxidized using ozone water to reduce the difference between the affinity of the exposed portion and the non-exposed portion.

When the ozone water used for surface oxidation was flowed into the drain pipe as it is, it was concerned that ozone will generate | occur | produce in a drain pipe, and it will adversely affect the other apparatus connected with the drain pipe. Thus, with the valve 606 closed, the alkali developer was poured into the alkali developer supply port 604 from the cup side so as not to contact the substrate, and a pool of alkaline developer 607 was formed at the bottom of the cup.

Next, as shown in FIG. 18B, the ozone water supply nozzle is rotated on the main surface of the substrate 600 while rotating the substrate 600 by the rotation mechanism of the substrate holding portion 601. 2 ppm of ozone water 609 is supplied to 608. The ozone water 609 supplied on the main surface of the processing target substrate 600 is modified on the main surface of the processing target substrate, and is then thrown into the cup by riding on the wall surface of the inner cup 602 at the outer periphery of the processing target substrate 600, Poured. The ozone released into the atmosphere in the cup was about 0.5 ppm, but the ozone released into the atmosphere was immediately decomposed by the vapor (mist) of the pre-collected developer. In addition, since the developer was a strong alkali (pH 13.8 or so), the ozone concentration in the poured ozone water decreased from 0.2 second to 0.2 ppm.

After completion of the first ozone water treatment, the substrate was rotated at a high speed to receive ozone water remaining on the main surface of the substrate in a cup, and after standing for 3 seconds (the ozone concentration was 1/1000 at the time of supply, FIG. 18 (c)), the valve ( 606 was opened, and the developer 613 containing ozonated water (that is, almost all ozone was decomposed into oxygen) was discarded in the drain pipe.

Fig. 21 shows the time change of the ozone gas concentration (addition-dependent ozone water to developer (pH = 13.8)). As shown in Fig. 21, comparing the addition of the developer to ozone water (the conventional method) and the addition of the ozone water to the developer (the method of the present invention) clearly shows that the method of the present invention shortens the treatment time. You can see that you can try. In addition, the above-mentioned leaving time (3 seconds) was determined with reference to FIG. Fig. 22 also shows the relationship with the pH of the time required for the residual ozone concentration to be 1/10.

Next, as shown in FIG. 19D, the developer 612 is supplied to the developer supply nozzle 611 on the main surface of the substrate 600 to be processed. At this time, after developing, the valve 606 at the bottom of the cup was opened in consideration of washing the main surface of the substrate with ozone water, so that the developer used for the treatment was accumulated at the bottom of the cup. The phenomenon took about 60 seconds.

Next, as shown in Fig. 19E, the processing target substrate 600 is rotated to sprinkle the developing solution to collect the developing solution 612 at the bottom of the cup (Fig. 19E). The ozone water was supplied to the main surface of the processing substrate 600 by the ozone water supply nozzle 608 (second ozone water treatment process) (Fig. 19 (f)). This ozone water is used for the purpose of removing the dissolution product and the swelling layer adhering on the chemically amplified resist pattern formed by the development on the main surface of the substrate. As shown in Fig. 6, the liquid is poured onto the processed developer that has been collected in the lower portion of the cup in advance. Since the treated developer has a pH of about 13, it is capable of sufficiently decomposing ozone in ozone water. For this reason, ozone generated in the atmosphere in the cup was decomposed in contact with the mist of the developer in the cup, and ozone in the poured ozone water could be sufficiently decomposed in a few seconds. As shown in Fig. 20 (h), the valve at the bottom of the cup was opened, and the decomposed ozone water was discharged to the drain pipe together with the treated developer.

By these treatments, a 110 nm wide wiring pattern could be formed on the main surface of the substrate with high dimensional accuracy and almost no defects, and again dry etched to form a wiring having excellent electrical characteristics. In addition, by almost completely decomposing ozone used in these series of steps in a cup, the treatment can be performed without releasing ozone into the environment.

In the present embodiment, after the second ozone water treatment step, the cup valve is opened to dispose of the waste liquid. However, in the case of continuous processing, the waste liquid is collected by closing the valve and the first ozone water treatment process of the next substrate is completed. After the second sheet, the developer used for the second ozone water treatment process can be reduced, and the amount of waste can be reduced, and the load on the environment can be reduced.

In this embodiment, although the developing solution supply line in a center cup is provided separately, it is not limited to this, It can take various forms, such as supplying from the upper part of a cup by moving a developing nozzle. In addition, the ozone water supply method and the developer supply method are not limited to this, but various developer supply nozzles, rinse solution supply nozzles, ozone water supply nozzles, and the supply methods thereof that are disclosed can be used. In addition, the position of the valve which communicates with a drain pipe is not limited to the position shown in figure, Any form may be sufficient as long as it can form an appropriate pool.

In this embodiment, although ozone water was used for the process before and behind developing developer supply, it is not limited to this. When the difference in affinity for the developing solution in the exposed region and the non-exposed region is small, the first ozone water treatment step may not be performed. In addition, in the case where adhesion of the dissolved product to the resist pattern hardly occurs after the development treatment, the second ozone water treatment step may not be performed.

In addition, although this embodiment is an application example to an ArF exposure process, it is not limited to this. In the developing process for the resist film to be used for _{KrF (248 nm), F 2} (157 nm) exposure processes using excimer radiation, high acceleration, a low-acceleration electron beam exposure, X-ray exposure, EUV exposure is applicable.

By the way, as shown in Fig. 21, the release of ozone into the atmosphere differs greatly in the order of chemical liquid mixing. First, when ozone water is present, the diffusion of ozone from the ozone water into the atmosphere begins, so that the concentration may be high before the alkali is supplied, and the ozone released into the atmosphere is gradually decomposed, but exists in a stable state. Throw it away. However, when alkali exists in advance and the vapor pressure of alkali is relatively high like tetraammonium hydroxide (TMAH) used in this embodiment, since alkali exists also in the atmosphere where alkali exists, ozone water will be poured there. Ozone released into the atmosphere by the physical shock poured out of the ground is decomposed by alkali that already exists in the atmosphere, and ozone in ozone water is also decomposed into alkali, so that ozone in the finished ozone water can be efficiently decomposed as in the present embodiment. .

This treatment is not limited to decomposition of the ozone water used at the time of development, and can be applied to other ozone water use processes.

In addition, this invention is not limited to the said embodiment, A various deformation | transformation can be implemented in the range which does not deviate from the summary.

As described above, according to the present invention, by applying an oxidizing liquid having an oxidizing action to the photosensitive resist film after exposure and oxidizing the surface of the photosensitive resist film, the contact angle between the exposed portion and the exposed portion of the non-exposed portion with respect to the developer is changed. In the micro area, by reducing the difference in the development speed in the initial stage of development caused by the magnitude of the area ratio of the exposed portion to the non-exposed portion in the local area and making the velocity and direction of the developer flow in the initial stage of development uniform. The dimension difference can be suppressed. In addition, a large number of generated particles resulting from the developing step can be prevented from adhering to the surface of the resist film, and the yield can be improved.

Claims (15)

Applying a photosensitive resist film on the substrate; Exposing to the photosensitive resist film; Applying an oxidizing liquid having an oxidizing action to the surface of the exposed photosensitive resist film, and pretreating the developer before supplying the developer to form an oxide layer by oxidizing the surface of the resist film with the oxidizing liquid; Supplying a developer to the photosensitive resist film whose surface is oxidized, and developing the resist film; And cleaning the substrate by supplying a cleaning liquid to the surface of the substrate to be processed. The pattern forming method according to claim 1, wherein the pretreatment is performed until a contact angle between the developer and the cleaning solution with respect to the photosensitive resist film decreases. The pattern forming method according to claim 1, wherein an aqueous solution containing at least one of ozone, oxygen, carbon monoxide and hydrogen peroxide is used as the oxidizing liquid. The method of claim 1, wherein in the pretreatment, the oxide layer is formed so that 5 nm or more is not formed in the depth direction of the resist film. The pattern forming method according to claim 4, wherein an aqueous solution having an ozone concentration of 5 ppm or less is used as the oxidizing liquid. The pattern forming method according to claim 1, wherein in the pretreatment, the oxide layer is formed by oxidizing the surface of the photosensitive resist film so that the polymer forming the resist film is not decomposed by the oxidizing liquid. The process according to claim 1 or 2, wherein, in the pretreatment, an eroding layer in which the polymer constituting the resist film in the oxide layer is decomposed by the oxidizing liquid is formed in a depth direction of the resist film. Forming a swelling layer in which the developer is soaked in the erosion layer when the developer is supplied onto the photosensitive resist film; And supplying said washing | cleaning liquid on a to-be-processed board | substrate, and peeling the said swelling layer. The pattern formation method characterized by the above-mentioned. The method of claim 1, wherein the developing solution is supplied to the photosensitive resist film by relatively moving the substrate to be treated and the developing solution ejecting nozzle while discharging the developing solution to the surface of the photosensitive resist film with the developing solution ejecting nozzle. A pattern formation method characterized by forming a developer film. The pattern forming method according to claim 1, wherein the oxidative liquid supplied to the surface of the photosensitive resist film is removed, and the surface of the substrate to be treated is dried. The process of claim 1, further comprising applying the oxidizing liquid and thinning the liquid film made of the applied oxidizing liquid; And forming said developer film in a state where a thin film of liquid is formed. The pattern forming method according to claim 1, wherein the developing step includes a step of stirring the developer film after formation of the developer film. Supplying an alkaline solution to a chemical solution holding portion provided outside the substrate to be treated with a thin film formed on its main surface; Supplying ozone water, which is an aqueous solution containing ozone, on the main surface of the substrate to be treated, thereby modifying the surface of the thin film, and inducing the ozone water used for the modification to the chemical liquid holding portion in which the alkaline solution is held; Decomposing ozone in ozone water induced in the chemical liquid holding part by an alkaline solution held in the chemical liquid holding part; And discharging ozone water from which the alkaline solution and ozone are decomposed from the chemical liquid holding unit. Supplying an alkaline solution to a chemical solution holding portion provided outside the substrate to be treated with a thin film formed on its main surface; Supplying ozone water, which is an aqueous solution containing ozone, to modify the surface of the thin film on the main surface of the substrate to be treated, and inducing the ozone water used for the modification to the chemical liquid holding portion in which the alkaline solution is held; Decomposing ozone in ozone water induced in the chemical liquid holding part by an alkaline solution held in the chemical liquid holding part; Supplying an alkali solution onto the main surface of the substrate to be treated whose surface has been modified, and selectively etching the thin film with the alkali solution, and retaining the alkaline solution used for etching in the chemical liquid holding portion; And discharging the alkaline solution and ozone water from which ozone is decomposed from the chemical liquid holding unit. Supplying an alkali solution on the main surface of the substrate to be formed with a thin film on the main surface, and selectively etching the thin film with the alkaline solution; Retaining an alkaline solution used for the etching in a chemical liquid holding unit provided outside the target substrate; Supplying ozone water, which is an aqueous solution containing ozone, to the main surface of the substrate to be etched to clean the main surface of the substrate, and inducing the ozone water used for cleaning to the chemical liquid holding portion; Decomposing ozone in ozone water induced in the chemical liquid holding part by an alkaline solution held in the chemical liquid holding part; Drying the to-be-processed substrate subjected to washing; And discharging ozone water from which the alkaline solution and ozone are decomposed from the chemical liquid holding unit. Supplying an alkaline solution to a chemical solution holding portion provided outside the substrate to be treated with a thin film formed on its main surface; Supplying ozone water, which is an aqueous solution containing ozone, on the main surface of the substrate to be treated to modify the surface of the thin film, and inducing the ozone water used for the modification to the chemical liquid holding portion in which the alkaline solution is held; Supplying an alkaline solution on a main surface of the substrate to be modified in which the thin film is modified to selectively etch the thin film, and retaining the alkaline solution used for etching in the chemical liquid holding portion; Inducing the ozone water used for cleaning to the chemical liquid holding portion while exposing and cleaning the main surface of the substrate to be treated with which the thin film is etched with ozone water; Decomposing ozone in ozone water induced in the chemical liquid holding part by an alkaline solution held in the chemical liquid holding part; Drying the cleaned substrate to be processed; And discharging ozone water from which the alkaline solution and ozone are decomposed from the chemical liquid holding unit.